The first component of the proposed project consists of the development and administration of a maternal and infant health survey of Puerto Rican women in the United States and Puerto Rico. Information on the determinants of infant health is urgently needed for this disadvantaged Hispanic subgroup, which has been identified as a target for special attention by the Public Health Service because of this high rates of neonatal, postneonatal, and infant mortality. Our project will be based on a sample of infants drawn from birth and death (infant) certificates for 1993. Information provided on these vital records will be supplemented with a followback survey of the infants' mothers. Detailed information will be obtained on maternal health habits during pregnancy, prenatal care, well-baby care, and illnesses/accidents during the early months of life. In addition, data will be collected on the migration process, acculturation, marriage patterns, and family/social supports. These data will be released as a public use data file which will serve as a valuable resource for future investigations of infant health among Puerto Ricans. A second component of the project entails analyses of key infant health outcomes. These analyses will focus on the determinants of low birth weight and infant mortality among Puerto Ricans, including maternal health habits during pregnancy (e.g nutrition; smoking; alcohol and drug use) and prenatal care. Key analytic issues to be examined are: a) the effects of maternal migration and acculturation on the health outcomes of infants; b) the interrelated effects of family structure, economic well-being, and kin networks on infant health/survival; and c) the processes underlying variation by geographic locale in the birth outcomes of mainland Puerto Rican women.